The present invention concerns devices for temporary attachment to loads for imparting lifting movement thereto and particularly to a lift device for frictional engagement with an inner wall surface of the load.
The concept of providing extensible load lifting devices engagable with load wall surfaces is disclosed in the prior art. Generally speaking, such devices utilize complex linkages which enable radial extension or adjustment of the linkages to effect load engagement. The foregoing coupled with the human factor renders the prior art devices susceptible to malfunction and accident load disengagement. If the loads lifted with such devices are sizable, as is usually the case, accidental loss of a load can result in substantial damage and severe injury in addition to possible destruction of the article lifted.